Isotope analyses to asses sediment cores from freshwater lakes in Jiangsu Region
2 Karlsruhe Institute of Technology Institute of Applied Geosciences
3 Potsdam University Institute of Environmental Sciences and Geography
P 4.4 in Environment and Pollution
The lakes in the Jiangsu province of China provide water to 30 million residents. Pollution of the lakes has been ongoing for decades in spite of efforts to reduce pollution. In 1993 alone, one billion tons of wastewater, 450,000 tons of garbage, and 880,000 tons of animal waste were dumped into the shallow lake Taihu. So lake Taihu was taken over by a massive bloom in May 2007.
The sediment cores of two lakes (Taihu and Yangcheng) are predicted to record the interaction of the sediment with the water column. Isotope and organic matter (d13C, 15N, TIC, NDOC (non-dissolvable organic Carbon), NDON (non-dissolvable organic nitrogen), d 13C-non-target-GC-CF-IRMS-MS), and element analyses were carried out to improve our understanding of the history and fate.
The inorganic parameters show differences between the possible precipitated Ca-species and the belonging anions. d13C-TIC shows values starting from marine carbonate in the deepest layer to fresh water carbonate in the upper layers of lake Taihu. d13C-TIC in lake Yangcheng shows an inverse trend.
The organic parameters show that each core has a different history and fate of the OM. These are preserved for the d13C-NDOC, d15N-NDON as well as the compound 13C-non-target-GC-CF-IRMS-MS. The found OM had different time-dependent sources. The sources of organic matter also change by time with the sediment core depth.
This investigation provides an improved understanding of the interaction between sediment and lake water.